<template>
  <div class='xtx-carousel' @mouseenter="stop()" @mouseleave="start()">
<!-- 图片容器 -->
    <ul class="carousel-body">
    <!-- 显示的图片加上fade -->
      <li class="carousel-item" v-for="(item,i) in sliders" :key="i" :class="{fade:index===i}">
        <RouterLink v-if="item.hrefUrl" :to="item.hrefUrl">
          <img :src="item.imgUrl" alt="">
        </RouterLink>
         <div v-else class="slider">
          <RouterLink v-for="goods in item" :key="goods.id" :to="`/product/${goods.id}`">
            <img :src="goods.picture" alt="">
            <p class="name ellipsis">{{goods.name}}</p>
           <p class="price">&yen;{{goods.price}}</p>
          </RouterLink>
         </div>
      </li>
    </ul>
    <!-- 上一张 -->
    <a @click="toggle(-1)" href="javascript:;" class="carousel-btn prev"><i class="iconfont icon-angle-left"></i></a>
    <!-- 下一张 -->
    <a @click="toggle(1)" href="javascript:;" class="carousel-btn next"><i class="iconfont icon-angle-right"></i></a>
    <!-- 指示器 -->
    <div class="carousel-indicator">
    <!-- action 激活点 -->
      <span @click="index=i" v-for="(item,i) in sliders" :key="i" :class="{active:index===i}"></span>
    </div>
  </div>
</template>

<script>
import { onUnmounted, ref, watch } from 'vue'
export default {
  name: 'XtxCarousel',
  props:{
      //轮播图数据
      sliders:{
          type:Array,
          default:()=>[]
      },
      //是否自动轮播
      autoPlay:{
        type:Boolean,
        default:false
      },
      // 间隔时长,
      duration:{
        type:Number,
        default:3000
      }
  },
  setup(props){
      //控制显示图片的索引
      const index=ref(0)

      //1.自动轮播的逻辑
      let timer=null
      const autoPlayFn=()=>{
        //防止定时器重复添加
        clearInterval(timer)
        //自动播放,每隔多久切换索引
        timer=setInterval(()=>{
          index.value++
          if(index.value>=props.sliders.length){
            index.value=0
          }
        },props.duration)
      }
      //需要监听sliders数据变化,判断如果有数据且autoplay是true
      watch(()=>props.sliders,(newVal)=>{
        if(newVal.length &&props.autoPlay){
          autoPlayFn()
        }
      },{immediate:true})
      //2.鼠标进入暂停,离开开启自动播放(有开启条件)
      const stop=()=>{
        if(timer) clearInterval(timer)
      }
      const start=()=>{
        if(props.sliders.length&&props.autoPlay){
          autoPlayFn()
        }
      }
      //3.点击点点可以切换上一张和下一张
  const toggle=(step)=>{
    //将要改变的索引
    const newIndex=index.value+step
    // 超出的情况,太大了
    if(newIndex>(props.sliders.length-1)){
      index.value=0
      return
    }
    // 超出的情况,太小了
    if(newIndex<0){
      index.value=props.sliders.length-1
      return
    }
    //正常
    index.value=newIndex
  }

  //4.组件卸载时,清楚定时器
  onUnmounted(()=>{
    clearInterval(timer)
  })
      return{index,stop,start,toggle}
  }
}
</script>
<style scoped lang="less">
.xtx-carousel{
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel{
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0,0,0,0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background:  #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0,0,0,.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev{
        left: 20px;
      }
      &.next{
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
// 轮播商品
.slider {
  display: flex;
  justify-content: space-around;
  padding: 0 40px;
  > a {
    width: 240px;
    text-align: center;
    img {
      padding: 20px;
      width: 230px!important;
      height: 230px!important;
    }
    .name {
      font-size: 16px;
      color: #666;
      padding: 0 40px;
    }
    .price {
      font-size: 16px;
      color: @priceColor;
      margin-top: 15px;
    }
  }
}
</style>